Sail-based electrical generation system and method

ABSTRACT

An energy generating system includes a first pair of sails, configured for opposing reciprocal swinging motion in response to a flow of fluid therepast, and a first generator assembly, mechanically coupled to the first pair of sails, configured to generate electrical energy from the opposing reciprocal swinging motion of the first pair of sails.

PRIORITY CLAIM

The present application is a continuation of U.S. patent applicationSer. No. 13/917,815, filed on Jun. 14, 2013 and entitled SAIL-BASEDELECTRICAL GENERATION SYSTEM AND METHOD, the disclosure of which isincorporated herein by reference in its entirety.

BACKGROUND

Hydroelectric dams and windmills are two of many “green” energytechnologies that allow the generation of electricity without burningfuel or creating pollution. However, hydroelectric dams and windmillspresent a number of challenges that limit their economic andtechnological viability. First, these technologies are verysite-specific. A hydroelectric generating facility requires sufficientwater head (i.e. vertical drop) and a constant water supply, coupledwith a site that is suitable for a dam. Essentially all goodhydroelectric dam sites in the United States have already been used, andenvironmental and wildlife-related opposition to blocking river flowsessentially precludes the construction of any more significanthydroelectric generating facilities in the U.S. Hydroelectric systemsare also very expensive to construct and take many generations foreconomic payback.

While windmills do not involve blocking streams, they are onlyeconomically feasible in places with sufficient mass air flows. Typicalutility-scale wind generators have a relatively high wind threshold, anddo not operate in low winds (e.g. below about 7-10 mph). This limitswind generation to areas with relatively constant high winds. Moreover,since wind speeds fluctuate, wind generation is not as reliable as othersources, and thus is not viewed as being viable for generating basepower for an energy utility. Wind generation also presents some hazardsto birds and other wildlife, and can produce noise pollution.Additionally, useful sites for both wind and hydroelectric power areoften quite distant from population centers, thus involving longtransmission lines, towers, etc., and a concomitant loss of energy andefficiency.

Given the challenges associated with hydroelectric and wind-basedgeneration of electricity using conventional methods, other methods ofgenerating electricity from wind and water are desirable. The presentdisclosure seeks to address one or more of the above issues.

SUMMARY

It has been recognized that it would be desirable to have a system andmethod for generating electricity from wind and/or water that is simpleand economical to implement.

It has also been recognized that it would be advantageous to have asystem and method for generating electricity from wind or water that canoperate in relatively low speed flows.

It has also been recognized that it would be advantageous to have asingle system that can generate electricity from both wind and water.

In accordance with one aspect thereof, this disclosure provides anenergy generating system that includes a first pair of elongate arms,having proximal and distal ends, configured for substantiallysymmetrically opposing reciprocal swinging motion in a substantiallyhorizontal plane. A first pair of substantially vertical sails are eachattached at the distal end of one of the elongate arms, the sails beingconfigured to drive opposing reciprocal swinging motion of the arms inresponse to a flow of fluid therepast. A first generator assembly isattached to the proximal ends of the first pair of arms, and isconfigured to generate electrical energy from the substantiallysymmetrical opposing reciprocal swinging motion of the arms.

In accordance with another aspect thereof, this disclosure provides asail-based energy generating system that includes a first pair ofsubstantially vertical sails, attached at distal ends of a pair ofelongate arms. The sails are configured to drive opposing reciprocalswinging motion of the arms in response to flow of fluid therepast. Atleast a portion of the first sails are pivotally moveable about asubstantially vertical axis, whereby a pitch of the sails is adjustableto drive the opposing reciprocal swinging motion. A first generatorassembly is attached to the proximal ends of the elongate arms, and isconfigured to generate electrical energy from the substantiallysymmetrical opposing reciprocal swinging motion of the arms.

In accordance with yet another aspect thereof, the disclosure provides amethod of generating electrical energy. The method includes disposing afirst pair of sails in a flowing fluid, the sails being mounted ondistal ends of first opposing arms, and periodically adjusting a pitchof the first pair of sails so as to generate an opposing reciprocalswinging motion of the first opposing arms in response to flow of thefluid past the first sails. The method further includes capturingmechanical energy of the opposing reciprocal swinging movement of theopposing arms in a first generator assembly and generating electricalenergy therefrom.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional features and advantages of the invention will be apparentfrom the detailed description which follows, taken in conjunction withthe accompanying drawings, which together illustrate, by way of example,features of the invention, and wherein:

FIG. 1 is a perspective view of an embodiment of a hydrosail electricalgenerating device mounted upon a floating barge;

FIG. 2 is a side view of the floating hydrosail electrical generatingsystem of FIG. 1;

FIG. 3 is a top view of the floating hydrosail electrical generatingsystem of FIG. 1 with the opposing reciprocal arms at their inwardmostposition and configured for outward motion, showing how adjustment ofthe pitch of the sails produces the opposing reciprocal motion;

FIG. 4 is a top view of the floating hydrosail electrical generatingsystem of FIG. 1, with the opposing reciprocal arms at their outwardmostposition and configured for inward motion, showing how adjustment of thepitch of the sails produces the opposing reciprocal motion;

FIG. 5 is a top view of an embodiment of the crank and generator systemof a sail-based electrical generating system in accordance with thepresent disclosure;

FIG. 6 is a partial side view of the generator and associated structureof the embodiment of FIG. 5;

FIGS. 7A and 7B are top views of the arms and sails with the sails inoppositely pitched orientations, respectively, showing one embodiment ofa mechanism for adjustment of the pitch of the sails;

FIG. 8 is a detail diagram showing an embodiment of a portion of apurely mechanical sail pitch control mechanism;

FIG. 9 is an illustration of a portion of an electrically controlledsail pitch control mechanism;

FIGS. 10-13 are side views of several exemplary sail configurations thatcan be used with a sail-based electrical generating system in accordancewith the present disclosure;

FIG. 14 is a top views of an embodiment of an arm and sail, showing oneembodiment of a mechanism for adjustment of the pitch of a rudder;

FIG. 15 is a detail top view of the rudder pitch control mechanism of

FIG. 14;

FIG. 16 is a side view of an embodiment of a hydrosail electricalgenerating device mounted upon a bridge pier in a river;

FIG. 17 is a perspective view of another embodiment of a hydrosailelectrical generating device mounted upon a fixed structure in a body ofwater;

FIG. 18 is a side view of an embodiment of a combined hydrosail andaerosail device mounted upon a floating barge;

FIG. 19 is a perspective view of an embodiment of an aerosail electricalgenerating device mounted upon a fixed, elevated structure;

FIG. 20 is a side view of the aerosail device of FIG. 19;

FIG. 21 is a perspective view of an embodiment of an aerosail electricalgenerating device mounted upon a wind generator; and

FIG. 22 is a perspective view of an embodiment of an aerosail electricalgenerating device mounted in a trailing orientation upon a windgenerator nacelle.

DETAILED DESCRIPTION

Reference will now be made to examples illustrated in the drawings, andspecific language will be used herein to describe the same. It willnevertheless be understood that no limitation of the scope of thedisclosure is thereby intended. Alterations and further modifications ofthe inventive features illustrated herein, and additional applicationsof the principles of the various aspects of the disclosure, asillustrated herein, which would occur to one skilled in the relevant artand having possession of this disclosure, are to be considered withinthe scope of the disclosure.

As used herein, positional and directional terms, such as “front,”“back,” “top,” “bottom,” “above,” “below,” “in,” “out,” “up,” “down,”and the like, are to be interpreted relative to the respectiveillustrations in the drawings. These terms are used for the purpose ofdescription in connection with the drawings only, and do not necessarilyindicate a specific direction, position or orientation relative to anyother thing or any other positional or directional reference system,unless otherwise indicated. Those of skill in the art will recognizethat the apparatus described herein may be used in a variety oforientations in which positional and directional terms could be useddifferently.

Advantageously, a sail-based electrical generating system has beendeveloped, as disclosed herein. This system converts slow-movingcurrents of water and air into electrical energy. It can be deployed incertain locations in which other designs cannot be used to generatepower. For example, the system disclosed herein can be retrofitted to anexisting windmill.

Viewing FIG. 1, an energy generating system 10 in accordance with thepresent disclosure generally includes a pair of elongate arms 12, havingproximal ends 14 and distal ends 16, configured for substantiallysymmetrically opposing reciprocal swinging motion in a substantiallyhorizontal plane. The proximal ends 14 of the arms 12 are pivotallyattached to and supported by a generator assembly 17. A pair ofsubstantially vertical sails 18 are attached at the distal ends 16 ofeach of the elongate arms 12, the sails 18 being at least partiallyimmersed in a flowing fluid 20 such as water, and configured to drivethe opposing reciprocal swinging motion of the arms 12 in response toflow of the fluid therepast. That is, the arms 12 are driven togetherand apart in a generally horizontal sweeping motion by the sails 18 inresponse to fluid flow therepast. The direction of flow of the fluid 20is indicated by arrow 22. The sails 18 can also include a rudder 21 attheir trailing edge, the rudder being configured to pivot with respectto the main sail body 19 in a manner similar to aircraft rudders.

The term “fluid” as used herein, has reference to any liquid or gas. Theflowing fluids that are primarily contemplated by the present disclosureare water and wind, but the system described herein can conceivably beused with other fluids, whether liquid or gas. The term “sail” as usedherein is intended to refer to any device that functions like a sail,whether rigid, semi-rigid or flexible. The figures show variousembodiments of sails having a substantially rigid panel or body,configured similar to the vertical stabilizer of an aircraft, thoughother types and configurations of sails can also be used, includingflexible sails. It will also be apparent that the sail panel or body canbe substantially solid, or it can have one or more interior spaces forinternal structure, such as a rudder control linkage, etc.

The reciprocal swinging motion of the arms 12 is illustrated in theviews of FIGS. 3 and 4, which show top views of a pair of arms 12 andsails 18, showing how adjustment of the pitch of the sails 18 producesthe opposing reciprocal motion. In FIG. 3 the opposing reciprocal arms12 are at their inwardmost position and configured for outward motion,as indicated by arrows 24. In FIG. 4 the opposing reciprocal arms 12 areat their outwardmost position and configured for inward motion, asindicated by arrows 26. The sails 18 pivot or “tack” back and forth inthe current flow, indicated by arrow 22, and thus move the long arms 12in a swinging motion.

In the embodiment of FIGS. 3 and 4, each sail 18 is pivotable upon itsrespective arm 12. When the arms 12 reach their closest point, shown inFIG. 3, the pitch of each sail 18 is mechanically switched. In FIG. 3the orientation of the sails 18 prior to this pivoting action is shownin dashed lines at 28 and the direction of pivoting of the sails isshown by arrows 30. With the sails 18 in the position as shown in solidlines in FIG. 3, the direction of flow 22 of the fluid 20 pushes againstthe sails 18 in a direction that pushes the arms apart, as indicated byarrows 24. When the arms 12 reach their farthest point, shown in FIG. 4,the pitch of the sail 18 is mechanically switched again, pivoting in thedirection of arrows 32 from the position established in FIG. 3 and shownin dashed lines at 34, back to its previous position, shown in solidlines in FIG. 4. With the sails in the position shown in FIG. 4, theflow 22 of the fluid again pushes against sails in a manner that movesthe arms 12 back together, in the direction of arrows 26, and theprocess repeats. This process can repeat so long as the fluid flow issufficient to do so.

In the sail-based generating system 10 shown in FIGS. 1 and 2, thegenerator assembly 17 is supported upon a floating barge 36, which isattached to a fixed anchor 38 in the flowing fluid 20. A generatingsystem of this type with the sails immersed in flowing water can bereferred to as a “hydrosail” system and the sails as “hydrosails.” Theflowing fluid 20 can be a river or a region that has tidal flow, forexample. Other bodies of flowing water can also be used. The mechanicalenergy of the opposing reciprocal swinging motion of the arms 12 istransmitted through a gear train or reduction gear assembly, discussedin more detail below, that is associated with the generator assembly 17,and converted to electrical power by a generator. A power conditioningunit 40 can be associated with the generator assembly 17, in order totransform the generated power (e.g. DC power) to AC suitable for use byAC devices or for transmission over a general power distribution system.An electrical power line 42 extends from the generator assembly 17 andpower conditioning unit 40 to transport the electrical power to itsintended destination.

The sail-based generating system 10 shown in FIGS. 1 and 2 can utilizelow speed water flows, like the type commonly found on rivers, andbarges incorporating this type of system can be anchored in a river toprovide quick, easy, cheap, self-contained units that generateelectrical power. Since many cities are located along rivers,transmission lines to transport the electrical power to the end user canoften be shortened. Hydrosail generation units on barges can be arrangedin many ways, such as lined up end-to-end or side-by-side to utilizeshallower flows, while allowing room for river traffic and debris flows.Additionally, since rivers flow continuously, hydrosails can providecontinuous power that can provide base energy for an energy utility.

The hydrosail energy generating system shown in FIGS. 1-4, supportedupon floating barges, can be modular, and can be almost any desiredsize, from small limited use units up to large utility scale systems.These can be very useful for generating power in remote areas. Forexample, a barge-mounted hydrosail device can be towed to a remote areaand put into a river or stream to generate electricity for a remotecabin, or for construction workers, hunters, campers, etc. at a singleremote site. The size of the hydrosail unit can be large or small,depending upon the size of the stream and the power needs. When the workat the remote site is completed, the unit can simply be towed away onthe river or other body of water. On the other hand, multiplebarge-mounted units can be placed in a river or other body of water togenerate power for a city, for example. These units can be moored inlocations that keep them out of the way of river traffic, yet allow thegeneration of power from the flowing water.

The way in which the mechanical swinging motion of the arms 12 iscaptured and harnessed can vary. Top and side views of an embodiment ofa mechanism for capturing energy from a pair of swinging reciprocal armsand generating electricity therefrom are shown in FIGS. 5 and 6. Thereciprocal arms 12 with sails 18 at their distal ends 16 are attached ata pivot point 50 at their proximal ends 14 to an arm support structure52. The generator assembly 17 includes a generator 54, which generatesthe electrical power, and this power is modified if necessary by thepower conditioning unit 40 and transmitted via the power line 42, asdiscussed above.

Mechanical energy from the swinging arms 12 is transmitted to thegenerator 54 via a drive linkage that includes twin pivoting links 56,which are each pivotally attached at one end to a respective arm 12, andare pivotally attached together at their other ends. A drive rod 58 ispivotally attached at one end to the pivoting links 56 at the pointwhere these two links 56 come together, and at its other end to a gearwheel 60. The swinging arms 12 transmit the sails' mechanical energy tothe generator 54 via the drive rod 58, which operates much like a pistonrod in an internal combustion engine or the drive rods of asteam-powered locomotive. When the arms 12 swing outward, as indicatedby arrows 62 in FIG. 5, this motion is transmitted to the drive rod 58via the pivoting links 56, causing the drive rod 58 to push in thedirection of arrow 64 in FIG. 5, driving the gear wheel 60 in thedirection of arrow 65. After the arms 12 reach their outward swinginglimit, the change of pitch of the sails 18, discussed above, will causethe arms 12 to reverse direction and begin to draw together. At thebeginning of this reversal of motion the drive rod 58 will pass over thetop dead center point 66 of the gear wheel 60 and begin to pull the gearwheel so as to continue its clockwise rotation.

The drive linkage not only transmits the mechanical energy of the arms12 but also coordinates the swinging motion of the arms 12 and makesthis motion symmetrical, thus preventing or canceling out any unbalancedtorque. Those of skill in the art will recognize that the dimensions andconnection points for the pivoting links 56 and drive rod 58 can beselected with reference to the position and diameter of the gear wheel60 so that the reciprocating swinging motion of the arms 12 causes thedrive rod 58 to continuously rotate the gear wheel.

As shown in the top view of FIG. 5 and the side view of FIG. 6, the gearwheel 60 has teeth that intermesh with the teeth of a reduction gear 67,which is attached to a shaft 68 of the generator 54. In this way therotation of gear wheel 60 is transmitted to the generator 54. The gearwheel 60 and reduction gear 67 form a gear train or reduction gearassembly that transmits the mechanical energy of the swinging arms 12 tothe generator assembly 17. It will be apparent to one of skill in theart that the diameter of the gear wheel 60 and the dimension of themoment arm created by the connection of the drive rod 58 thereto, aswell as the gear ratio between the gear wheel 60 and the generator 54and the relative mass of these components can be selected to provide adesired speed range and momentum for these elements. A flywheel 70 canalso be attached to the shaft 68 of the generator 54. The momentum ofthe flywheel 70 helps maintain smooth rotation of the generator shaft68, and also helps to maintain smooth swinging motion of the arms 12 andunidirectional rotation of the gear wheel 60.

It will be apparent to those of skill in the art that the particularmechanism shown and described herein for converting swinging reciprocalmotion of the arms 12 into unidirectional rotational motion of the gearwheel 60 and of the generator 54 is only one of many mechanisms thatcould be used to convert the mechanical swinging motion of the arms intoelectrical energy. Any mechanism that can convert the mechanicalswinging motion of the arms into electrical energy can be used inconnection with the system 10 herein, including, for example, those thatuse electrical generators that are not based on rotational motion.

As noted above, in order to drive the opposing reciprocal swingingmotion of the arms 12, the system 10 includes a mechanism forselectively adjusting the pitch of at least a part of each sail 18. Themechanism for switching and controlling the pitch of the sails 18 orpart of the sail can be configured in various ways, from simple andrelatively inexpensive purely mechanical systems, to more advancedcomputer-controlled power-actuated systems. Provided in FIGS. 7A and 7Bare top views of an arm 12 with a pivotally attached sail 18, showingoperation of one embodiment of a mechanism for adjusting the pitch ofthe sail 18. The direction of flow of the fluid 20 is indicated byarrows 22. The sail 18 is shown pitched in one direction in FIG. 7A andoppositely pitched in FIG. 7B, so that the flow of the fluid 20 causesswinging motion of the arm 12 about its pivot point 50 in the directionof arrow 72 in FIG. 7A and in the direction of arrow 74 (the oppositedirection) in FIG. 7B.

The pitch shifting mechanism shown in FIGS. 7A and 7B can be a purelymechanical system. In this embodiment, the sail 18 includes a pivot arm76 that is affixed to the sail 18 and pivots with the sail. Attached tothe opposite ends of the pivot arm 76 are cables 78, 80. These cablesextend along (or through) the arm 12 to corresponding arms of a pitchlever 82 that is pivotally attached to the arm 12. A close-up view ofthe pitch lever 82 and related structure is shown in FIG. 8. The pitchlever 82 includes an actuating arm 84 that is positioned to alternatelycontact each of two shift rods 86, 88 at the extreme ends of the motionof the arm 12. When the arm 12 swings to one extreme, the actuating arm84 of the pitch lever 82 will contact the left shift rod 86 and bepushed (by virtue of the motion of the arm 12) to the position shown inFIG. 7A. The position of the pitch lever 82 just before contacting theleft shift rod 86 is depicted in FIG. 8, and the position of the pitchlever 82 just after contacting the left shift rod 86 is depicted in FIG.7A.

Rotation of the pitch lever 82 at this point of the cycle is transmittedvia the cables 78, 80 to the pivot arm 76 of the sail 18, and thusrotates the sail to the position shown in FIG. 7A, initiating motion ofthe arm 12 in the direction of arrow 72. When the arm 12 swings to theopposite extreme, shown in FIG. 7B, the actuating arm 84 of the pitchlever 82 will contact the right shift rod 88 in a similar manner, thusrotating the pitch lever 82 to the position shown in FIG. 7B. Thismotion of the pitch lever 82 is transmitted via the cables 78, 80 to thepivot arm 76 of the sail 18, and will rotate the sail 18 to the positionshown in FIG. 7B, causing motion of the arm 12 in the direction of arrow74.

A mechanism can be provided to hold the pitch lever 82 and/or the sail18 in a given position during transit of the arm 12 through each sweepdirection. Shown in FIG. 8 is an over-center spring mechanism that canbe used for this purpose. This mechanism includes an over-center tensionspring 90, which is attached between a fixed point on the arm 12, and apoint on the actuating arm 84 of the pitch lever 82, on opposite sidesof the pivot point 92 of the pitch lever 82. This configuration of thespring 90 naturally biases the pitch lever 82 away from its centeredposition and toward its two extreme tilted positions, shown in FIGS. 7Aand 7B. Any sort of mechanism for fixing the extreme tilted positions ofthe pitch lever 82 and limiting its rotational range of motion can beused. The strength of the spring 90 and the force involved to rotate thepitch lever 82 can be selected to balance the force for holding the sail18 in a given position and the force involved in switching the positionof the pitch lever 82. Those of skill in the art will recognize thatother mechanisms for holding the pitch lever 82 and/or the sail 18 in agiven position during transit of the arm 12 through each sweep directioncan also be used. For example, a detent mechanism (not shown) canpotentially be used for this purpose.

A mechanism can also be provided for limiting the range of motion of thesail 18. One embodiment of such a mechanism is shown in the top views ofFIGS. 7A and 7B. This mechanism includes a horizontal crossbar 83,attached to the arm 12 near the pivotal attachment point of the sail 18on the arm 12. The crossbar 83 includes a pair of upright stops 85 atopposite ends of the bar. These stops 85 are positioned to contact thesail 18 at selected extreme points in its pivoting range, so as tophysically prevent the sail 18 from pivoting beyond that point. The sail18 pivots above the crossbar 83, and contacts one stop 85 when itreaches one extreme of its motion, and contacts the other stop 85 whenit pivots to the opposite end of its motion. A side view of a similarcrossbar 135 and one of its upright stops 137 are shown in the side viewof a sail 134 in FIG. 12. The crossbar 135 is attached to the arm 138within a slot 139 of the sail panel 136. The sail panel 136 can includea reinforced region 141 that is configured to contact the upright stops137, so that repeated contact with each shifting of the sail does notdamage the sail 134. It will be apparent that other types of mechanismscan be used for setting and controlling the range of motion of the sail18.

It is to be appreciated that many other types and configurations ofmechanical systems can be used for shifting the pitch of the sail 18.For example, as one alternative, a cam-based system can also be used.Such a system is illustrated in FIG. 5. In this embodiment, a pitchlever 44 is pivotally attached to the arm support structure 52, and isattached to control cables 49, 51 that extend along or through theswinging arms 12 for control of the pitch of the sail 18. These cablesfunction like the cables 78, 80 described above with respect to FIGS.7A, 7B and 8.

The pitch lever 44 includes an actuating arm 45 having an elongate slot46, in which is a pin 46. The pin fits into a cam slot 47 that islocated in a cam wheel 48, which is engaged with the gear wheel 60.Rotation of the gear wheel 60 rotates the cam wheel 48. The cam slot 47can have any desired shape relative to the center axis of the cam wheel48, so that the pin 46 follows a desired path (e.g. a non-circular path)as the cam wheel 48 rotates. The motion of the pin 46 is converted intoback-and-forth tipping motion of the actuating arm 45 of the pitch lever44, depending on the position of the cam wheel, thus pivoting the pitchlever at certain times relative to the reciprocal motion of the arms.The reciprocal swinging motion of the arms 12 thus controls the pitcharm 44, which pulls on the cables 49, 51 to adjust the pitch of the sail18.

As an alternative to a purely mechanical pitch adjustment system,various types of power-operated actuators (e.g. electrical, hydraulic,pneumatic, etc.) can be used for controlling the sail pitch. These canuse cables, rods, or other actuating members, and can be computercontrolled. For example, referring to FIG. 8, rather than moving thepitch lever 82 by contact with the shift rods 86, 88, the pitch lever 82can instead include an actuating arm 91 that is attached to actuatingcables 93, 94, shown in dashed lines. These cables 93, 94 can beattached to a purely mechanical actuating system, or they can beattached to electrical or hydraulic actuators that pull on therespective cables 93, 94 at the appropriate time in order to shift thepitch of the sail 18.

One embodiment of a power-operated actuator for a cable-type system isshown in FIG. 9. In this figure, an electrical actuator 96 is connectedto a cable drum 98, which includes two cables 100, 102 that areoppositely wound around the drum 98. Rotation of the drum 98 in onedirection simultaneously causes one cable to retract and allows theother to extend. This type of cable control system can be used todirectly actuate the sail pitch control cables 78, 80, or it can be usedto pull on the pitch lever cables 93, 94 in order to shift the pitchlever 82, or it can be used to actuate rudder control cables, asdiscussed below.

Other power-operated pitch control devices can also be used, includingelectrical or hydraulic actuators like those that are commonly used inaircraft, and these can be mounted in various locations. For example,rather than using a pitch adjustment mechanism that is positioned aroundthe proximal ends of the arms 12 and uses cables to move the sail 18,the pitch adjustment can be made via aircraft-type actuators that areinstalled directly in, on or adjacent to the sail 18, with powertransmission devices (e.g. electrical or hydraulic lines) extendingalong the arm 12 from suitable power sources located near the generatorassembly 17. Other configurations can also be used.

A control system for controlling a power-actuated pitch controlmechanism using electronic sensors is illustrated in FIGS. 7A and 7B.This system includes an arcuate sensor track 104 that is affixedadjacent to the arm 12 near the pivot point 50 of the arm, with a scanhead 106 attached to the arm and aligned with the sensor track 104. Asthe arm 12 swings, motion of the scan head 106 adjacent to the sensortrack 104 produces an electronic signal that is transmitted to acontroller 108. This signal can indicate the position, speed anddirection of motion of the arm 12. With this information, the controller108 can send signals to control actuators to adjust the pitch of thesail 18 at any desired time and to any desired degree.

Advantageously, a computer-controlled and power-actuated pitchadjustment system like that disclosed herein can be configured to changethe sail pitch at predetermined set points to improve efficiency of thestroke of the swinging arms 12. For example, to optimize power output,the position of the sail 18 can be adjusted at any sweep position orthroughout the sweep range, rather than simply having a single staticpitch angle set at each end of the sweep cycle. In this way, thestresses on the system 10 and the velocity of swinging can be controlledor adjusted, such as to promote constant velocity rotation of the gearwheel 60 and therefore of the generator 54.

The configuration of the sails 18 (e.g. size, shape, connectionmechanism, etc.) can also affect the type and size or power requirementsof the sail actuation and control system, and also the power output ofthe system 10. There are several variables that can be selected withrespect to the configuration and operation of the sails 18. Selection ofthe type and configuration of the sails 18 can depend on the size andscope of the installation. Several examples of sails 18 having differentconfigurations are shown in side views in FIGS. 10-13.

One variable that can be selected with respect to the configuration andoperation of the sail 18 is the location and type of connection of thesail 18 to its respective arm 12. Another variable that can be selectedis the nature and extent of moveable portions of the sail 18. The sails18 that are described above and illustrated in FIGS. 3-5 and 7A-B arefull-pivoting sails. That is, the entire sail 18 is configured to pivoton the respective arm 12. However, sails having moveable rudders canalso be used. The sails 18 shown in FIGS. 1-2 include a main sail body19 and a moveable rudder 21. As described below, the sails shown inFIGS. 10-13 also include a main sail body and a moveable rudder. Therudders can help control and drive repositioning of the respective sail,and can also contribute to the opposing reciprocal swinging motion ofthe respective arm. An exemplary mechanism for adjusting the pitch ofthe rudder is described below with respect to FIGS. 14 and 15.

Referring to FIG. 10, a sail 110 can be configured having a main sailbody 112 that is fixedly attached to its swinging arm 114, but includesa pivotal rudder 116 at its extreme distal end. The main body 112 of thesail 110 does not pivot with respect to the arm 114, but the rudder 116can pivot about a generally vertical axis 118 to drive the reciprocalswinging motion of the arm 114. The relative size and shape of therudder 116 can be selected to provide a desired operation of this sail110, and is not limited to the specific size, shape or proportions shownin FIG. 10. Because the main body 112 of this sail 110 is fixed on thearm 114, the angle of the main body 112 does not change relative to thearm 114, but changes relative to the direction of flow of the water orother fluid with swinging of the arm 114. The rudder 116 is moveablelike the rudder of an aircraft or boat, and changes angle with respectto the body 112 of the sail 110 in order to shift its direction. Thus,in this configuration, only a portion of the sail 110 changes pitch withrespect to the arm 114, and drives the swinging motion of the arm 114.

Alternatively, sails can be configured having both a pivoting main bodyand a rudder that also pivots with respect to the main body. Variousconfigurations having this feature are shown in FIGS. 1-2 and 11-13. Thelocation of the pivoting connection of the sail to the arm can vary. Inthe embodiment of FIG. 11, a sail 120 is pivotally attached to itsrespective arm 122 at a leading edge 124 of the main sail body 126, andalso includes a pivotal rudder 128. In this configuration the entiresail 120 pivots about a substantially vertical axis 130 that extendsthrough the leading edge 124 connection location. The pitch of theentire sail 120 is adjustable about this axis 130 to promote theswinging motion of the arm 122. The rudder 128 also pivots about asubstantially vertical axis 132 that is along the leading edge of therudder 128. Thus the entire sail 120 can change pitch with respect tothe arm 122, and the rudder 128 can change pitch with respect to thesail body 126.

Having a pivoting rudder in combination with a pivoting sail body can bevery desirable. When a sail is pivoted and fixed at some angle withrespect to its arm, it is then driven with respect to the current flow,and as the arm swings the angle of the sail will gradually change withrespect to the current to a position almost parallel with the currentflow. This aspect of fully pivoting sails is illustrated in FIGS. 3 and4. In this latter portion of the arm's stroke, the power provided by theflow will diminish because the angle of attack of the sail panel isreduced. Advantageously, if the rudder is also pivoted with respect tothe sail, the sail and rudder combination can have a higher effectiveangle of attack and can therefore provide additional driving force inthis portion of the stroke. However, at the extreme points in the arm'smotion, only a relatively small amount of force will be required tochange the pitch of the sail to overcome the force of the current uponit and reverse its angle to begin to push the arm back in the otherdirection. To facilitate the reverse pitch motion of the sail, therudder can be straightened (which will be facilitated by the fluid flowitself) and the pitch of the sail can be reversed in the mannerdiscussed above. Since the sail panel is also pivotal, the entire sailwill “come about” to re-engage the current when the arm reaches each endof each sweep, as described above. When the system swings or pivots thesail to come about at this point, it will again fully engage the currentand commence the power phase of the arm's sweep back in the oppositedirection. The rudder can also be used during pivoting of the main sailpanel to provide additional force for pivoting the panel.

Another alternative sail configuration is shown in FIG. 12, in which asail 134 is provided having a main body 136 that is pivotally attachedto its arm 138 at a single pivot point near a “midpoint” or “middleaxis” 140 that is located back some distance from the leading edge 142of the sail. In this configuration the entire sail 134 pivots about themiddle axis 140, such that the pitch of the entire sail 134 isadjustable to promote the swinging motion of the arm 138, in the mannerdiscussed above.

The precise location of the middle axis 140 can vary. In the embodimentshown in FIG. 12, the middle axis 140 is positioned aft of the sail'saxis of symmetry, so that the sail section forward of the middle axis140 (designated at 146) has more surface area than the aft section(designated at 148) of the sail 134. With this configuration, thecurrent pushing on the sail 134 will tend to keep the sail 134 in itspitched position, rather than tending to straighten it out. With thesail main body 136 in a fixed orientation with respect to the arm 138,in the course of the sweep of the arm 138 the angle of the sail 134 withrespect to the current flow will gradually turn from a full-on powertack to a position closer to parallel with the current flow, asdiscussed above. After the system swings or pivots the sail 134 to comeabout at this point, it will again fully engage the current and commencethe power phase of the arm's 138 sweep back in the opposite direction,and the current flow will again tend to keep the sail 134 in its pivotedorientation.

The sail 134 of FIG. 12 also includes a moveable rudder 150 at itstrailing edge, which can pivot in the same manner as the ruddersdescribed above, to provide additional control and power and assist inpivoting the main body 136 of the sail 134 at the end of each portion ofthe swinging stroke. Again, the relative size and shape of the rudder150 relative to the sail 134 as a whole can vary from that shown in thefigures.

Shown in FIG. 13 is another alternative embodiment of a sail 154 havinga main body 156 that is pivotally attached to its arm 158 at a doublepivot point along a “middle axis” 160 that is located back some distancefrom the leading edge 162 of the sail. In this configuration the entiresail 154 pivots about the middle axis 160, such that the pitch of theentire sail 154 is adjustable to promote the swinging motion of the arm158, in the manner discussed above. The sail 154 of FIG. 13 alsoincludes a moveable rudder 163 at its trailing edge, to provideadditional control and power and assist in pivoting the main body 156 ofthe sail 154 at the end of each stroke. Again, the relative size andshape of the rudder 163 can vary from that shown in the figures.

It is to be appreciated that the various sail configuration alternativesshown in the figures herein can be mixed and matched in various ways.Different combinations of connection types and connection points of thesails on their respective arms can be used. Likewise, the size and shapeof the sails and rudders can also vary in many ways. The sails andrudders shown in FIGS. 10-13 are generally rectangular and symmetrical.However, sails and rudders having different shapes can also be used. Forexample, the sail 18 shown in FIG. 2 has a slightly tapered shape, witha tapered leading edge. On the other hand, the sails 208, 218 shown inFIGS. 16 and 17 and discussed below have more of a shark fin shape.Other shapes can also be used.

It will also be apparent that the pivoting connection point of the sailpanels upon the respective arms are different in the embodiments ofFIGS. 11, 12 and 13. As noted above, in the configuration of FIGS. 12and 13, the sails 134, 154 are pivotally attached to their respectivearms near a “midpoint” of the respective sail panel 136, 156. In theembodiment of FIG. 11, however, the sail body 126 is pivotally attachedto its arm 122 at or near the leading edge 124 of the sail body 126.Either of these configurations can be used. It is to be understood thatthe variables of moveable rudder versus no moveable rudder, and midpointattachment versus leading edge attachment can be mixed and matched invarious combinations.

As noted above, the configuration of the sails can affect the type andsize or power requirements of the sail actuation and control system. Forexample, where a sail has a midpoint attachment, as illustrated in FIGS.12 and 13, the sail can be bigger for a given actuation and controlsystem since forces and stresses will be reduced due to the mid-sailattachment point, relative to a leading edge attachment point (as inFIG. 11) for a similarly sized sail.

The discussion above related to FIGS. 7A, 7B and FIG. 8 outlined anembodiment of a mechanical sail pitch adjustment mechanism. A similarsystem can be used for adjusting the orientation of a moveable rudder ofa sail. Shown in FIGS. 14 and 15 are top views of an embodiment of asail 164 attached to a swinging arm 166, the sail having a moveablerudder 168. The arm 166 and sail 164 are shown configured to swing inthe direction of arrow 170 and at a position toward one extreme of therange of swinging of the arm. At this point the fluid flow, indicated byarrow 172, is at a significant angle with respect to the arm 166 and isnearly parallel with the sail 164.

The arm 166 includes a pitch lever 174 and a pair of cables 176, 178that extend to the sail 164. The arm support structure 180 includes apair of shift rods 182, which are positioned to contact a lever arm 184of the pitch lever 174 whenever the main arm 166 swings to eitherextreme of its range of motion. When contacted in this way, the pitchlever 174 rotates in the manner discussed above with respect to FIGS.7A, 7B and FIG. 8, causing it to pull on the cables 176, 178. The arm166 can include a cable tensioning system for maintaining tension onthese cables 176, 178. One embodiment of a cable tensioning system isshown in FIG. 14, and includes a first bent lever 181, which isgenerally V-shaped with two opposing arms, and is pivotally attached tothe arm 166 adjacent to the pitch lever 174. The arms of the first bentlever 181 include pulleys 183 at their distal ends and tension springs185 that extend back to connection points on the arm 166. The cables176, 178 on either side of the arm 166 extend through the respectivepulleys 183 of the first bent lever 181, which automatically maintainstension in these cables 176, 178 by the spring-assisted swinging motionof the first bent lever 181.

Following the first bent lever cable tensioning system, the cables 176,178 are guided along the arm 166 by a series of pulleys 186, and passthrough a second bent lever 188 prior to their connection to oppositeends of a pivot lever 190. The second bent lever 188 is pivotallyattached near the distal end of the arm 166, but is not spring loaded.Its function is to guide the cables 176, 178 as the sail 164 pivots backand forth. As shown in the detail view of FIG. 15, the pivot lever 190is attached to the rudder pivot lever 192 by a push rod 194. When thepivot lever 190 is rotated in one direction, this causes the push rod194 to rotate the pivot lever 192 of the rudder 168 and therefore rotatethe rudder 168 in the opposite direction.

In addition to the barge-mounted configuration shown in FIGS. 1-4, asail-based energy generating system in accordance with the presentdisclosure can be attached to a fixed structure in a flowing body ofwater, such as a bridge pier or other solid structure. Two embodimentsof such a system are shown in FIGS. 16 and 17. In the embodiment of FIG.16, an electrical generator and reduction gear base unit 200 isvertically slidably attached to a bridge pier 202, and includes afloatation buoy 204 that allows the entire base unit 200 to rise andfall with the level of the water. While only one swinging arm 206 isvisible in the side view of FIG. 16, it is to be understood that asubstantially identical arm is positioned on the far side of the visiblearm 206. The swinging arms 206 extend from the base unit 200, with sails208 disposed at the distal ends of the arms 206 and immersed in thewater. An electrical cable 210 can extend from the base unit 200 to thebridge pier 202 to couple power from the base unit to the local powergrid (not shown).

In another embodiment, shown in FIG. 17, a hydrosail electricalgenerating base unit 212 is vertically slidably attached to a verticalpole 214, which is anchored in the water. Like the other embodimentsshown herein, the base unit 212 includes an electrical generator andreduction gear, with reciprocating arms 216 that extend from thegenerator unit and sails 218 at the distal ends of the arms 216. Thesails 218 are immersed in the water, and generate reciprocal swingingmotion in response to the flow of water therepast. In this embodiment,the generator and reduction gear base unit 212 includes a floatationbuoy 220 that allows the entire unit to rise and fall with the level ofthe water, while a power line 222 transmits energy to the local powergrid (not shown).

The sail-based energy generating system embodiments discussed above havebeen presented as being configured for generating energy from flowingwater. However, water is not the only flowing fluid that can be used togenerate energy. This same type of device can also be used in air togenerate electricity from wind power, as shown and described withrespect to FIGS. 18-22 below. A wind-based version of this device isreferred to herein as an “aerosail.” Moreover, air and water-basedenergy generation techniques can be used separately or together. Thatis, the hydrosail configuration can be augmented with aerosails as well.An example of a combined hydrosail and aerosail device mounted upon afloating barge is shown in a side view in FIG. 18. In thisconfiguration, a combined hydrosail and aerosail energy generatingsystem 224 is mounted upon a floating barge 226. The barge 226 isanchored in flowing water 228 in the manner discussed above with respectto FIGS. 1 and 2, and the hydrosails 230 are immersed in the water atthe ends of arms 232 that are positioned in a trailing orientation withrespect to the direction of flow 234 of the water 228. The arms 232 areattached to a first generator assembly 236, which can include areduction gear assembly and sail pitch control devices, as discussedabove, and generates electricity from the back and forth swinging motionof the arms 232.

A second generator assembly 238 is also attached to the barge 226, andincludes a pair of arms 240 that extend from it. These arms 240 supporta pair of sails 242 which are positioned in the air above the water 228to draw energy from wind. In the same way flowing water causes the backand forth swinging motion of the hydrosail arms 232, the wind will causeback and forth swinging of the aerosail arms 240, thus generatingelectricity from the wind via the second generator assembly 238 and itsassociated reduction gear assembly, etc. Control of the pitch of theaerosails 242 and their rudders 244 can utilize any of the controlmechanisms mentioned above, and the sail and rudder shape and connectionaspects discussed above with respect to FIGS. 10-13 can also be chosenas desired. This generating system 224 is thus configured to generateelectrical energy from motion of either or both the hydrosail arms 232and the aerosail arms 240.

Given the different density of wind versus water, the aerosail panels242 can be significantly larger than corresponding hydrosails 230 forcomparable power output. Those of skill in the art will recognize thatwater flowing at a given velocity possesses significantly more kineticenergy than wind flowing at the same speed, simply due to the greaterdensity of water. Consequently, a sail of a given size and shape,immersed in flowing water will produce more energy than the same sizesail positioned in wind having the same velocity. Thus, the wind andwater sails can be sized relative to the density of their respectiveflowing fluids, so that the typical energy output of the wind andwater-based generators is substantially balanced, at least under certainconditions.

It is also to be appreciated that the two sail sets of a combinedhydrosail and aerosail energy generating system can be designed oroptimized to balance the system, so that a roughly comparable amount ofenergy is produced by the wind and water sail systems. Additionally oralternatively, the sails can be sized and dynamically adjusted in theirpitch so that the in-and-out motion of both pairs of sails—both aboveand below the water line—runs at a substantially similar period at thesame time. The sails can also be designed so that the air flow generatesa larger level of the mechanical movement or energy than the water flow,or vice versa.

Those of skill in the art will recognize that wind changes speed anddirection frequently, unlike rivers, which generally flow in only onedirection and have a velocity that can be relatively constant.Consequently, the aerosail base unit 238 is pivotally attached to itssupport 246, so that it can pivot about a vertical axis 248 with changesin wind direction. While the view of FIG. 18 shows the aerosail arms 240and hydrosail arms 232 substantially aligned with each other, this isfor illustrative purposes only. It will be appreciated that thiscondition will only occur when the direction 250 of air flow happens tocoincide with the direction 234 of the flowing water. In order toprovide adequate resistance to overturning regardless of the angularorientation of the aerosail arms 240 relative to the orientation of thehydrosail arms 232, the barge 226 can have a size and shape that areselected with regard to these anticipated forces.

The sail pitch and rudder pitch control systems can be configured toadjust the relative angles of these features to accommodate differentwind conditions and to reduce damaging stress upon the system. Forexample, when winds are particularly high, automatic pitch adjustmentdevices can be configured to reduce the angle of attack of the sailand/or rudder during each portion of the driving phase of the arm'sswinging motion in order to reduce mechanical stress on the system andmaintain a desired speed of reciprocation of the arms. On the otherhand, when winds are light, the system can be configured to increase theangle of attack in order to obtain maximum energy from the wind.

Various embodiments of sail-based energy generating systems inaccordance with the present disclosure having only aerosails can also beprovided. Shown in FIGS. 19 and 20 are views of an embodiment of anaerosail electrical generating system 252 mounted upon a fixed, elevatedstructure 254. This unit operates in the same way as the hydrosail andaerosail configurations discussed above, and harnesses wind energy,rather than flowing water. The system 252 includes a pair of elongatearms 256, having proximal and distal ends, configured for substantiallysymmetrically opposing reciprocal swinging motion in a substantiallyhorizontal plane. A pair of substantially vertical sails 258 areattached at the distal end of each of the elongate arms 256, and thesesails are positioned to be driven in opposing reciprocal swinging motionby the wind. A generator base unit 260 is attached to the proximal endsof the pair of arms 256, and is configured to generate electrical energyfrom the swinging motion of the arms, as discussed above. Control of thepitch of the sails 258 and rudders can utilize any of the controlmechanisms mentioned above, and the sail and rudder shape and connectionaspects discussed above with respect to FIGS. 10-13 can also be chosenas desired. The generator unit 260 is pivotally attached to a supportbase 262, so that it can rotate about a vertical axis 264 in response tochanges in wind direction. As shown in FIGS. 19 and 20, the aerosailelectrical generation device can be attached to a fixed, elevatedstructure, such as a building or a pole. Where the system 252 isattached to a building, as shown in FIG. 19, it can be configured toprovide power to that building alone, or it can be connected into thelocal power grid.

In another embodiment, shown in FIGS. 21 and 22, an aerosail energygenerating system 266 can be attached to a support pole 268 of aconventional propeller-type wind generator 270, thus providing anadditional power generating device attached to an existingpower-generating structure. In this embodiment, the aerosail device 266is attached with arms 272 and sails 273 oriented in a trailingorientation upon the nacelle 274 of the wind generator 270, and thereduction gear and generator that are associated with the swinging arms272 can be located within the wind generator nacelle 274. In thisconfiguration, wind force upon the aerosail device 266 not onlygenerates additional power, but also provides a wind vane effect uponthe generator nacelle 274, thus augmenting the system that maintains itsorientation into the wind. As with other embodiments discussed herein,control of the pitch of the sails 273 and rudders can utilize any of thecontrol mechanisms mentioned above, and the sail and rudder shape andconnection aspects discussed above with respect to FIGS. 10-13 can alsobe chosen as desired.

The system disclosed herein thus provides a method for generatingelectrical energy in a distributed manner using water flow below a waterline and/or air flow. Providing this type of energy generating systemcan involve assembling a barge including opposing arms, the opposingarms having sails mounted on distal ends of the opposing arms. The bargecan float and be anchored in a low speed body of water, and can generatemechanical movement of the opposing arms from the air flow and the waterflow captured by the sails and the rudders. This mechanical energy canbe captured or harnessed and converted to electrical energy by agenerator.

This system and method is also highly scalable. It can be embodied in asmall device that attaches to a boat to generate small amounts of powerfor campers, for example, or it can be sized for utility-scale powergeneration for cities or factories, or any size in between. Those ofskill in the art will recognize that power generation and powerconditioning features, such as transformers, rectifiers and the like,can be selected as called for by the amount of current and voltage thatthe system generates.

Advantageously, this system generates electrical energy with very lowenvironmental impact, using air and water flows that are typicallyviewed as not enough to be practical. It is also believed to berelatively inexpensive to produce and operate, quick and easy to installor remove, and is believed to involve relatively low-maintenance.Furthermore, it is believed that this system will not significantlyaffect birds, fish or other marine life, or river and air flows, sinceit generates electricity with no pollution emmissions or fueling costs,and the swinging arms reciprocate at relatively low speeds.Additionally, the system disclosed herein is a distributed modular powergeneration system rather than a centralized generation system, and canbe attached to moving vehicles. For example, a system in accordance withthis disclosure can be mounted on a large ship, such as a tanker orcontainer ship, to provide additional electrical power for propulsion orother purposes. Many other applications and adaptations are alsopossible.

It is to be understood that the above-referenced arrangements areexemplary illustrations of the various aspects of the presentdisclosure. It will be apparent to those skilled in the art thatnumerous modifications of one or more of the disclosed examples can bemade without departing from the principles and concepts of the presentdisclosure and the appended claims.

What is claimed is:
 1. An energy generating system, comprising: a firstpair of sails, configured for opposing reciprocal swinging motion inresponse to a flow of fluid therepast; and a first generator assembly,mechanically coupled to the first pair of sails, configured to generateelectrical energy from the opposing reciprocal swinging motion of thefirst pair of sails.
 2. A system in accordance with claim 1, wherein thefirst sails are substantially vertically oriented.
 3. A system inaccordance with claim 2, wherein the first sails are at least partiallyimmersed in flowing water, and further comprising: a second pair ofsubstantially vertical sails, disposed in air above the flowing water,configured for opposing reciprocal swinging motion in response to a flowof wind therepast; and a second generator assembly, mechanically coupledto the second pair of sails, configured to generate electrical energyfrom the opposing reciprocal swinging motion of the second pair ofsails.
 4. A system in accordance with claim 1, wherein the first sailsare pivotally moveable, whereby a pitch of the sails is adjustable topromote the opposing reciprocal swinging motion.
 5. A system inaccordance with claim 1, wherein each sail includes a moveable rudder,configured to drive the opposing reciprocal motion thereof
 6. A systemin accordance with claim 1, wherein the first sails are at leastpartially immersed in flowing water.
 7. A system in accordance withclaim 6, wherein the first pair of sails and the first generatorassembly are disposed upon a floating support that is anchored in theflowing water.
 8. A system in accordance with claim 1, wherein the firstsails are substantially vertically oriented and are disposed in atrailing orientation upon a wind generator nacelle, wind force upon thefirst sails providing a wind vane effect upon the wind generatornacelle.
 9. A system in accordance with claim 1, further comprising: apitch control mechanism, configured for selectively adjusting a pitch ofat least a part of each sail, so as to drive the opposing reciprocalmotion thereof; and the first generator assembly includes a crankassembly, having a shaft, attached near a proximal end of each sail,configured to convert the opposing reciprocal motion of the sails intounidirectional rotational motion of the shaft; and an electricalgenerator, attached to the shaft, configured to generate electricalenergy from rotation of the shaft.
 10. A system in accordance with claim1, wherein the energy generating system is attached to an uprightsupport and the sails are positioned to be moved by wind.
 11. Asail-based energy generating system, comprising: a first pair ofsubstantially vertical sails, configured for symmetrical opposingreciprocal motion in response to a flow of fluid therepast; a pitchcontrol mechanism, configured for selectively adjusting a pitch of atleast a part of each sail, so as to drive the opposing reciprocal motionthereof; and a first generator assembly, mechanically coupled to thefirst sails, configured to generate electrical energy from the opposingreciprocal swinging motion of the first sails.
 12. A system inaccordance with claim 11, wherein the generator assembly furthercomprises: a crank assembly, attached to each sail, configured toconvert the opposing reciprocal motion of the sails into unidirectionalrotational motion of a shaft; and an electrical generator, coupled tothe shaft, configured to generate electrical energy from rotation of theshaft.
 13. A system in accordance with claim 11, wherein the first pairof sails are at least partially immersed in flowing water, and furthercomprising: a second pair of substantially vertical sails, positioned inair above the water, configured for symmetrical opposing reciprocalswinging motion in response to a flow of air therepast; and a secondgenerator assembly, attached to the second pair of sails, configured togenerate electrical energy from the symmetrical opposing reciprocalswinging motion of the second pair of sails.
 14. A system in accordancewith claim 13, wherein the first and second pairs of sails, the pitchcontrol mechanism, and the first and second generator assemblies aresupported upon a floating support that is anchored in the flowing water.15. A system in accordance with claim 11, wherein the energy generatingsystem is attached to a fixed structure positioned in the flowing fluid.16. A method of generating electrical energy, comprising: disposing afirst pair of opposingly reciprocally moveable sails in a flowing fluid;adjusting a pitch of the first pair of sails to drive opposingreciprocal swinging motion of the sails under force of the flowingfluid; and capturing mechanical energy of the opposing reciprocalswinging motion in a first generator assembly and generating electricalenergy therefrom.
 17. A method in accordance with claim 16, whereindisposing the first pair of opposingly reciprocally moveable sails in aflowing fluid comprises at least partially immersing the first pair ofsails in flowing water.
 18. A method in accordance with claim 17,further comprising: mounting the first sails and the first generatorassembly upon a floating support and anchoring the support in theflowing water; mounting a second pair of opposingly reciprocallymoveable sails in air above the water; attaching the second sails to asecond generator assembly; adjusting a pitch of the second pair of sailsto drive opposing reciprocal swinging motion of the second pair of sailsunder force of wind flowing therepast; and capturing mechanical energyof the opposing reciprocal swinging motion of the second sails in asecond generator assembly and generating electrical energy therefrom.19. A method in accordance with claim 16, further comprising disposingthe first sails and the first generator assembly upon an elevatedstructure, the first sails being positioned to generate opposingreciprocal motion from flow of wind therepast.
 20. A method inaccordance with claim 19, wherein the elevated structure comprises awind generator tower, and further comprising: disposing the first sailsin a trailing orientation upon a wind generator nacelle, wind force uponthe first sails providing a wind vane effect upon the generator nacelle.